Regarding the first schematic
I don't quite understand what it is you wish to achieve with this. The STUSB4761 is designed to regulate a supply voltage, according to the request of the conected device, and to monitor and limit the current. In your design, it doesn't get the chance to regulate anything.
Voltage regulation is already done by U1. And as it cannot regulate anything, it shouldn't matter whether or not you connect C17 and R28 to the FB pin.
While I haven't read every single word in the datasheet, I do believe that the STUSB4761 chip isn't designed to work this way. As you haven't said anything about in what way it isn't working, I will have to guess. My best guess is that the STUSB4761 senses that the 5 V supply from U1 is slightly off, either high or low. It tries to compensate for this by adjusting the pulse width and/or frequency on the OPTO_DRV pin. This, however, doesn't do anything, and the chip ends up in a fault situation, and doesn't turn on U4/U5.
Regarding the second schematic
Here you apparently haven't connected VDD to the supply voltage. Also, I don't understand why R14 is connected between TSENSE and OPTO_DRV. These may be simple mistakes, though.
But even if these are fixed, I don't give this a better chance at working. You still don't use STUSB4761 as a voltage regulator. OPTO_DRV now just drives a yellow LED, which in itself doesn't do anything useful.
My conclusion is that you are using the wrong device. The STUSB4761 is not designed for what you are trying to do, and (as mentioned before) it has also been discontinued. This means that it is no longer in production, and using it in a new design is not recommendable.
In other words: To achieve what you are trying to do, you will need to find a different part.
